1. Field of the Invention
This invention relates to digital indication type measuring apparatus and measured data storage apparatus therefor, and more particularly to improvements in digitial indication type measuring aparatus comprising an encoder connected to a measuring element for detecting a displacement of the measuring element, a counter for counting output signals from the encoder, and a digital indicator for indicating a value counted by the counter as a measured value.
2. Description of the Prior Art
In general, in measuring apparatus, such as slide calipers or a micrometer, for measuring a length of other dimension of an article, the displacement or movement value is measured of two measuring apparatus elements movable relative to each other, such as a measuring element which is movable relative to a main body of the measuring apparatus, or a slider which is movable relative to a column. A so-called "digital indication" type of such measuring apparatus for providing a digital indication of the measured value was heretofore known, one example of which comprises an encoder, a light source, a main scale, an index scale and a photoelectric transducer mounted in the main body of the measuring apparatus.
Compared with known measuring apparatus providing an analog indication of a measured value, the above-referenced digital indication type of measuring apparatus has the advantages of being, inter alia, more easily read, and easier to use because no special skill is required. however, in the conventional digital indication type of measuring apparatus, the indicating graduations used in the analog type of machine are simply replaced by a digital indicator. This has the disadvantage that the measured value indicated by the digital indicator must be read and transcribed by a worker in order for the measured value to be inputted into an independent or external computer or the like for computing a standard deviation, etc., or for use in quality control.
In order to overcome the aforementioned disadvantage, a digital indication type of measuring apparatus has heretofore been proposed wherein a digital output signal corresponding to the measured value is produced for inputting to an external computer. However, since it has been necessary to directly connect such digital indication type measuring apparatus to an external computer, such measuring apparatus has the practical disadvantage that the measurement site is restricted because of the installation requirements of the external computer. Consequently, the article to be measured must be removed from the work or processing site to a separate measurement site, thus decreasing work efficiency. In addition, the use of a simplified external computer which can be installed at the article processing site is made difficult by the temperature, vibration, noise and the like conditions present at the processing site. Moreover, the throughput capacity of such computers is limited. Also, the computers cannot be operated efficiently because measurements are generally made intermittently and take a long period of time to complete, which restricts the functioning of the computer for long periods of time. Further, such computers require preparation or maintenance to maintain the computers in a functioning condition.
Still further, the computational results in general are not obtained in real time and thus generally should be tabulated or displayed graphically, as well as data-analyzed to provide a reference or index for optimizing subsequent article processing. However, the measuring operation triggers the interrupt function of external computers, which prevents satisfactory utilization of the proper functions of an external computer.
In addition, the points of measurement generally vary with each article, which requires that the external computer be adjusted accordingly, thus necessitating an additional worker for this purpose. Further, the types of computations which can be performed is limited depending on the type of external computer which is connected to the measuring apparatus.
To overcome the above-described disadvantages of digital indication type measuring apparatus which is directly connected to an external computer, the use of a so-called data logger for temporarily storing the measured values has been proposed. However, the use of a general-purpose data logger for accumulation of the data from measuring apparatus requires a large-size device, which is particularly unsuitable for portable types of digital indication measuring apparatus.